Alessandro Poggi

Università degli Studi di Modena e Reggio Emilia, Modène, Emilia-Romagna, Italy

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Publications (8)29.87 Total impact

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    ABSTRACT: Anti-infective properties of biomedical materials are often achieved by loading or coating them with powerful bactericides. Undesirably, these bioactive molecules can damage the host cells at the biomaterial-tissues interface and, sometimes, even determine systemic toxic effects. The search for biomaterials able to actively resist infection while displaying a safe cytocompatibility profile towards eukaryotic cells is being progressively developed. Poly-(D,L)Lactic acid (PLA) is a broadly used resorbable material with established biocompatibility properties. The dissolving surfaces of a biodegradable material tend to be per se elusive for bacteria. Here, films of pristine PLA, of PLA blended with Vitamin E (VitE) and PLA blended with vitamin E acetate (VitE ac) were challenged in vitro with the biofilm-producers Staphylococcus epidermidis RP62A and Staphylococcus aureus ATCC25923. The bacterial adhesion properties of the different materials were investigated on small film disc specimens by a method based on microtiter plates. Adherent bacteria were quantified by both CFU plating and bioluminescence. Significant decrease of bacterial adhesion and biofilm accumulation was found on the surface of both the enriched polymers. These findings, together with the favorable intrinsic properties of PLA and the desirable bioactivities conferred by VitE, point up the VitE-blended PLA polymers as gentle anti-infective biomaterials.
    Journal of Biomedical Materials Research Part A 07/2014; · 2.83 Impact Factor
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    ABSTRACT: Biofilm production is the crucial pathogenic mechanism of the implant-associated infection and a primary target for new anti-infective strategies. Silver nanoparticles (AgNPs) are attracting interest for their multifaceted potential biomedical applications. As endowed with highest surface/mass ratio and potent antibacterial activity, they can profitably be applied as monolayers at biomaterial surfaces. Desirably, in order to minimize the risks of toxic effects from freely circulating detached nanoparticles, AgNPs should firmly be anchored to the modified biomaterial surfaces. Here we focus on a newly designed glass surface modified with AgNPs and on its antibiofilm properties. Link of a self-assembled monolayer of AgNPs to glass was obtained through preliminary amino-silanization of the glass followed by immersion in an AgNPs colloidal suspension. Static contact angle measure, AFM, TEM, UV-Vis spectroscopy, ICP atomic emission spectroscopy were used for characterization. Antibiofilm activity against the biofilm-producer Staphylococcus epidermidis RP62A was assayed by both CFU method and CLSM. Performances of AgNPs-glasses were: i) excellent stability in aqueous medium; ii) prolonged release and high local concentration of Ag(+) without any detaching of AgNPs; iii) strong antibiofilm activity against S. epidermidis RP62A. This AgNPs surface-modification can be applied to a large variety of biomaterials by simply depositing glass-like SiO2 films on their surfaces.
    Biomaterials 12/2013; · 8.31 Impact Factor
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    ABSTRACT: Staphylococcus aureus is the leading etiologic agent of implant orthopedic infections. Until recently S. aureus was considered a mere extracellular pathogen; it then turned out to be able to invade eukaryotic cells. Adhesion of S. aureus to peri-prosthesis tissues represents the starting of the infection pathogenesis and the first step of the subsequent internalization of S. aureus by host cells. In the present work the experimental observations on two epidemic clinical strains differing in their adhesin pattern demonstrate the crucial role of the fibronectin-binding protein A in the internalization process and suggest that CNA and Bbp adhesins can play a synergistic role by acting in the initial adhesion of S. aureus to osteoblasts, thus favoring the subsequent FnBPA-mediated internalization.
    The International journal of artificial organs 11/2011; 34(9):789-98. · 1.76 Impact Factor
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    ABSTRACT: Implant-related osteomyelitis is a severe and deep infection of bone that arises and develops all around an implant. Staphylococcus aureus is the first cause of osteomyelitis, whether implant-related or not. Bone is an optimal substratum for S. aureus, since this bacterium expresses various adhesins by which can adhere to bone proteins and to the biomaterial surfaces coated with the proteins of the host extracellular matrix. S. aureus is able not only to colonize bone tissues, but also to invade and disrupt them by entering bone cells and inducing cell death and osteolysis. Here we illustrate the pathogenetic mechanisms that can explain how the osteomyelitis sets in and develops around an implant.
    The International journal of artificial organs 11/2011; 34(9):781-8. · 1.76 Impact Factor
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    ABSTRACT: Extracellular DNA (eDNA) is an important biofilm component that was recently discovered. Its presence has been initially observed in biofilms of Pseudomonas aeruginosa, Streptococcus intermedius, Streptococcus mutans, then Enterococcus faecalis and staphylococci. Autolysis is the common mechanism by which eDNA is released. In P. aeruginosa eDNA is generated by lysis of a bacterial subpopulation, under control of quorum sensing system. In E. faecalis autolysis proceeds in a fratricide mode, resulting from a process similar to necrosis of eukaryotic cells. In Staphylococcus aureus autolysis originates by an altruistic suicide, i.e., a programmed cell death similar to apoptosis of eukaryotic cells. In S. aureus autolysis is mediated by murein hydrolase, while in S. epidermidis by the autolysin protein AtlE. In P. aeruginosa eDNA is located primarily in the stalks of mushroom-shaped multicellular structures. In S. aureus the crucial role of eDNA in stabilizing biofilm is highlighted by the disgregating effect of DNase I. eDNA represents an important mechanism for horizontal gene transfer in bacteria. eDNA and other microbial structural motifs are recognized by the innate immune system via the TLR family of pattern recognition receptors (PRRs).
    The International journal of artificial organs 11/2011; 34(9):824-31. · 1.76 Impact Factor
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 01/2010; 28(30).
  • Angewandte Chemie International Edition in English 01/1996; 35(2):202-204. · 13.45 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 07/1993; 24(29).

Publication Stats

36 Citations
29.87 Total Impact Points

Institutions

  • 2013–2014
    • Università degli Studi di Modena e Reggio Emilia
      Modène, Emilia-Romagna, Italy
  • 2011
    • Istituto Ortopedico Rizzoli
      • Medical Technology Laboratory
      Bolonia, Emilia-Romagna, Italy
  • 1993–2010
    • University of Pavia
      • Department of Chemistry
      Ticinum, Lombardy, Italy